When using regex, precompile needs to be done in order to increase the matching performance. Examples:
<pre>
    public class XxxClass {
        // Use precompile
        private static Pattern NUMBER_PATTERN = Pattern.compile("[0-9]+");
        public Pattern getNumberPattern() {
            // Avoid use Pattern.compile in method body.
            Pattern localPattern = Pattern.compile("[0-9]+");
            return localPattern;
        }
    }
</pre>